Sit at a desk in a comfortable chair. Place your feet flat on the floor, and sit up straight. Lift your wrist from resting on the keyboard. Take regular breaks between your typing tests. Type in a well-lit room.
Focus on the letters and punctuation your fingers are typing to increase your accuracy. Typing at the speed of light may be exciting, especially as you see your words per minute rating increase with each test you take, but if your accuracy is still below par, then you have not gained much.
Use a variety of online typing tests or pick different tests to take if you are using learn-to-type software. You will eventually memorize parts of a text if you type it repeatedly. This will not accurately reflect your improving speed and accuracy. Different tests also focus on various typing skills. So, taking a few types of tests can improve your skills in a variety of keystrokes.
Keep at it. Take at least a test a day, thinking of each keystroke you make. As your accuracy improves, work to increase your speed. Type the same test a few times to increase your speed and train your fingers to reach for each key faster and faster.